If Arctic charr Salvelinus alpinus is “the most diverse vertebrate,” what is the lake charr Salvelinus namaycush?

Fish and Fisheries
By: , and 



Teleost fishes are prominent vertebrate models of evolution, illustrated among old-world radiations by the Cichlidae of East African Great Lakes and new-world radiations by the circumpolar Arctic charr Salvelinus alpinus. Herein, we describe variation in lake charr S. namaycush morphology, life history, physiology, and ecology, as another example of radiation. The lake charr is restricted to northern North America, where it originated from glacial refugia and diversified in large lakes. Shallow and deepwater morphs arose in multiple lakes, with a large-bodied shallow-water ‘lean’ morph in shallow inshore depths, a small-bodied mid-water ‘humper’ morph on offshore shoals or banks, and a large-bodied deep-water ‘siscowet’ morph at depths > 100 m. Eye position, gape size, and gillraker length and spacing adapted for feeding on different-sized prey, with piscivorous morphs (leans and siscowets) reaching larger asymptotic size than invertivorous morphs (humpers). Lean morphs are light in color, whereas deepwater morphs are drab and dark, although the pattern is reversed in dark tannic lakes. Morphs shift from benthic to pelagic feeding at a length of 400–490-mm. Phenotypic differences in locomotion, buoyancy, and lipid metabolism evolved into different mechanisms for buoyancy regulation, with lean morphs relying on hydrodynamic lift and siscowet morphs relying on hydrostatic lift. We suggest that the Salvelinus genus, rather than the species S. alpinus, is a diverse genus that should be the subject of comparative studies of processes causing divergence and adaptation among member species that may lead to a more complete evolutionary conceptual model.

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Publication type Article
Publication Subtype Journal Article
Title If Arctic charr Salvelinus alpinus is “the most diverse vertebrate,” what is the lake charr Salvelinus namaycush?
Series title Fish and Fisheries
DOI 10.1111/faf.12114
Volume 17
Issue 4
Year Published 2016
Language English
Publisher John Wiley & Sons
Contributing office(s) Great Lakes Science Center
Description 14 p.
First page 1194
Last page 1207
Country United States; Canada
Other Geospatial Great Bear Lake; Great Slave Lake; Lake Superior; Rush Lake; Lake Mistassini
Online Only (Y/N) N
Additional Online Files (Y/N) N
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